Soluble vat dye intermediates



Patented Aug. 30, 1955 2,716,653 SOLUBLE VAT DYE JNTERMEDIAT-ES WilliamHardy, Bound Brook, and Harry E. Westlake, Jr., Somerville, N. J.,,assignors to American (yanamid Company, New York, N. Y., a corporationMaine No Drawing. Application May 21, 1952, Serial No. 289,202

1 1 Claims. v((31. 260-671) This invention relates to leucosulfuric/acid half esters of 2-amino-3-alkylsulfonyl anthraquinonehaving the following formula:

(I)SOaM The new :indan'threne vat dyestuffs show good =fastness to lightand oxidation, and are of .a desirable bright green-blue shade. :In:these indanthrenes, the :alkyl .sulfonyl groups behave :in an anomalousmanner: instead of lightening the shade and exerting :a hypsochromiceifect, which is normal when .alkyll sulfonyl groups are introduced intoother .dyes, in thiscasethe reverse takes place; a deeper :shade isobtained, {the :alloyl zSlllfOIlyl groups exhibiting .a bathochrorniceffect. The indanthrene vat dyestuffs for which the compounds of :thepresent invention are intermediates are not claimed in the presentapplication, forming the subject matter of our co-pending applicationSerial No. 289,201, filed May 21, 1951.

The leuco sulfuric acid half esters of the present invention areprepared from 'the corresponding 2-acetylaminoanthraquinonyl-3-alkylsulfones which are not claimed in the present application forming thesubject matter of our co-pending application Serial No. 289,203, filedMay 21, 1951.

The choice of acyl group on the amino group is not of particularsignificance, the purpose of the acylation being merely to protect theamino group during esteiification. Typical'acyl groups are thefollowing: formyl, acetyl, propionyl, butyryl, valeryl, and otheraliphatic carbonyl groups, and benzoyl, naphthoyl, lthenoyl. Obviously,.of course, the acyl group must not have substituents which will enterinto the reaction. Since the particular acyl group is of nosignificance, we prefer to use acyl groups from the cheap, low molecularweight acids, the acetyl group-being preferred.

The alkyl group in the '3-alkyl sulfonyl group may be any alkyl havingnot more than four-carbon atoms, such as methyl, ethyl, propyl,isopropyl, butyl, isobutyl, and secondary butyl.

While the preparation by the process in the present invention results inthe first instance in a crude product .in which the amino group isacylated, the principal use .of the .compounds of the present inventionin forming indanthrenes requires that the amino group be :free and thismay be effected very simply by a conventional hydrolysis reaction. Thepresent invention, therefore, includes not only the desired Z-aminocompounds but also the acylamino compounds from which they wereprepared.

While it is not desired to limit the present invention to any particularmethod of preparing the compounds, a very satisfactory process isdescribed in the examples and constitutes a preferred method.

The leuco sulfuric acid half esters of the present invention arenormally obtained in the form of their metal salts. The particular metalor cation on the sulfonic acid groups are more or less immaterial asthey do not materially affect the use of the compounds in the succeeding ring closing reaction to produce indanthrenes. Accordingly, anyof the common cations may be used, such as, for example, sodium,potassium, lithium, quaternary organic bases and the like. Because ofsolubility characteristics, there is some advantage in using thepotassium salt, but the invention is in no sense :limited thereto.

The invention will be described in greater detail in conjunction withthe following specific examples, ;the parts being by weight unlessotherwise specified:

Example 1 NH C 0-0 Ha S C Ha A mixture of 83 parts of sodium sulfide,21.2 parts of sulfur, 360 parts of pyridine, and 36 parts of water isstirred and heated until a complete solution is obtained. To this isadded 68.6 parts of 2-acetylamino-3- bromo anthraquinone. The mixture isstirred and heated until the reaction is complete and then is drowned in2000 parts by volume of water. The drowned mixture is distilled untilthe pyridine is removed. The hot residual solution is treated with partsof sodium chloride. When the mixture is cooled to 20 C., the sodiummercaptide precipitates. This is filtered and washed with 400 parts byvolume of 20% brine, and then reslurried in 200 parts by volume ofwater. Eighty parts of soda ash is added to the slurry, which is thenstirred at room temperature while 72 parts by volume of dimethyl sulfateis added gradually. The mixture is then stirred overnight. A yellowprecipitate appears which is filtered, Washed neutral, and dried. Thiscan be recrystallized from dichlorobenzene to give green-yellow crystalsof 2- acetylaminoanthraquinonyl-3-methyl sulfide.

Example 2 A mixture of 74 parts of 2-acetylaminoanthraquinonyl- S-methylsulfide and 700 parts by volume of glacial acetic acid is stirred whilea solution of 100 parts of potassium permanganate in parts of hot wateris added. The permanganate is washed into the mixture with an additional batch of 700 parts by volume of acetic acid. The mixture isstirred at the boil until oxidation is complete. It is then cooled to70, and a quantity of sodium bisulfite is added sufficient to decomposethe precipitated manganese dioxide. The mixture is drowned in 2000 partsby volume of ice and water. The precipitated2-acetylaminoanthraquinonyl-3-methyl sulfone is filtered, washedneutral, and dried. The sulfone can be recrystallized fromdichlorbenzene, giving pale yellow crystals.

Example 3 O-SOaK To 248 parts of alpha picoline is added gradually below30 C. 89.6 parts of chlorsulfonic acid. The mixture is stirred untilthoroughly mixed and then warmed to C. A finely divided mixture of partsof Z-acetylaminoanthraquinonyl-3-methyl sulfone and 26.8 parts of finelydivided iron is added gradually to the chlorsulfonic acidpicolinemixture. The mixture is then stirred at 40 C. until reduction andesterification is complete. It is drowned in a solution of 191.5 partsof sodium carbonate and 1150 parts by volume of water. The alphapicoline is removed by vacuum distillation. The mixture is filtered andthe precipitate is washed with hot water to a clear wash. The filtrateis salted to 23% potassium chloride concentration by volume and cooledto 20 C. The precipitated bright yellow diester potassium salt isfiltered and washed with saturated alkaline potassium chloride solution,followed by methanol, and dried under a vacuum. The leuco sulfuric acidester potassium salt of 2- acetylaminoanthraquinonyl-3-methyl sulfone isobtained. This is a bright yellow crystalline solid, quite soluble inwater. The leuco diesters of other 2-acylaminoanthraquinonyl-3-methylsulfones, such as propionyl and benzoyl, can be prepared similarly.

Example 4 CHrr-OzS O-SOaK 52 parts real of the esterifiedZ-acetylaminoanthraquinonyl-3-methyl sulfone, 490 parts by volume ofwater, and 44 parts by volume of a 50% aqueous sodium hydroxide solutionare heated gradually to C. and then held at 75 80 until hydrolysis ofthe acetylamino group is complete. The free amino compound thus preparedcan be isolated by salting out, or can be oxidized to form theindanthrene as follows. Nickel dioxide, prepared from 64 parts ofnickelous chloride is added in the form of a wet cake thoroughly stirredin at C. until ring closure has been effected, then the reaction mixtureis filtered hot, the cake washed with hot water and the filtrateconcentrated under reduced pressure to a volume of about 400 parts.Sufiicient potassium chloride is then added to produce a l5concentration by volume. The mixture is cooled. The potassium salt ofthe indanthrene tetraester precipitates out, is filtered and washed witha saturated potassium chloride solution. The product is a browncrystalline product which is soluble in water giving a solution whichfiuoresces green on dilution. If desired, it may be purified further byresalting from water with potassium chloride. When dyed by the usualmethods, cellulose fibers are dyed a bright green-blue of excellentfastness, especially to light.

The procedure of Examples 1 to 3 is followed replacing the dimethylsulfate with diethyl sulfate. The hydrolyzed 3-amino disulfuric halfester may be isolated if desired by salting out and filtration, or itmay be oxidized directly with nickel dioxide as described in Example 4to produce the corresponding indanthrene dyestuif. This product is abrown crystalline solid, soluble in water, the solution fluorescinggreen on dilution. When dyed on cellulose fibers by the usual method,bright green-blue shades are obtained of good fastness.

The procedure of Examples 1 to 3 is followed, replacing the methylationprocedure of Example 2 by slurrying the 2-acetylamino-2-mercaptoanthraquinone in 1000 parts by volume of ethanol, adding 37 parts ofbutyl iodide, and stirring at the boil. The yellow precipitate formsimmediately, it is preferably not filtered until the reaction mixturehas been cooled and stood for sufficient time to result in completeprecipitation. The diester produced is a bright yellow crystalline solidwhich is soluble in water. After hydrolysis of the acetyl group, asdescribed in Example 4, the free amino compound may be isolated, orpreferably, transformed into the corresponding indanthrene dyestufi bythe procedure of Example 4. A dye is obtained which dyes cellulosefibers by the usual processes bright greenish blue.

Example 7 0-SOsNa -NHC O-GH:

SO2GHa The procedure of Examples 1 to 3 is followed but the isolation iscarried out by means of a sufficient quantity of sodium salt to give thenecessary concentration of sodium ions to produce corresponding sodiumsalt. This product when hydrolyzed and transformed into the indanthrenedyestufi by the procedure of Example 4 produces a dye which can be usedin exactly the same manner as the product of Example 4 to produce thesame shades.

a 6 We claim: 7. The leuco sulfuric acid half ester of the formula 1.Leuco sulfurlc acid half esters of the formula O SO3K 0-SO3M NH: NHR' 0802GB; SOzR SO3K SO3M 8. Leuco sulfuric acid half esters of the formulawherein R represents an alkyl group of not more than four carbon atoms,R represents a radical selected from the group composed of hydrogen andan acyl radical, and M is a monovalent cation.

2. Leuco sulfuric acid half esters of the formula 1U -S02C2H5 O-SOaM0so3M SOaOH;

0-s 05M wherein M is a monovalent cation.

3. The leuco sulfuric acid half ester of the formula SOzGH:

-SOaK 4. Leuco sulfuric acid half esters of the formula SOzCzHu mint-oO-GH:

-souu wherein M is a monovalent cation.

5. The leuco sulfuric acid half ester of the formula SOzCaHu mien-o0-011! 6. Leuco sulfuric acid half esters of the formula S0:M wherein Mis a monovalent cation.

wherein M is a monovalent cation.

9. The leuco sulfuric acid half ester of the formula zCaHr -SOaK 10.Leuco sulfuric acid half esters of the formula (i)-SO:M

wherein M is a monovalent cation.

11. The leuco sulfuric acid half ester of the formula 0so;K

References Cited in the file of this patent UNITED STATES PATENTSFairweather et a1 Feb. 27, 1934 Klein Oct. 17, 1939

1. LEUCO SULFURIC ACID HALF ESTERS OF THE FORMULA